• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.303-308
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• 2001

Various organic solvents are most commonly using material in various factories, for examples, paint producting process and other industries, actually most of them are toxic materials, If many kinds of organic chemicals are concurrently exposed to workplace, toxidities can be influenced as additive effect or synergistic effect.(omitted)

• Journal of the Korean institute of surface engineering
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• v.37 no.2
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• pp.76-79
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• 2004

Nickel chloride coated protein chip plate was developed by using a spin coating method. The ability of histidine tagged protein adsorption was investigated at various solvents. The surface of plate has a large aggregated nickel complex with high density in water. However, the surface of plate has a very small size of aggregated nickel complex with low density in isopropanol. The ability of protein adsorption decreased as increasing the size of alkyl chain in various alcohol solvents. The mechanism on the ability of protein adsorption at the plate surface is discussed.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.11-17
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• 1998

Chitin is known as biodegradable natural polymer. In spite of various application of chitin derivatives from waste marine sources, commercial use of chitin has been limited due to high resistance to chemicals and the absense of proper solvents. We chitin prepared through the decalcification, bleaching and deproteination from Protunus trituberculatus shells by change of Hackman's method. Also, Microcrystalline chitin made by hydrolysis that was reduce made of resistance solvents used by dilute hydrochloric acid, ultrasonic and hydrogen peroxide. Crosslinked chitin derivatives were preparaed from chitin with crosslink agents(epichlorohydrin, 1,3-dichloropropanol) follwed by crosslinkage at 6C position. The effects of these parameters on chitin dervatives were invastigated by IR, DSC, XRD, BET, PSA and SEM. SEM analysis showed that both chitin and crosslinked chitin had a particle shaped morphology.

• Journal of the Korean Applied Science and Technology
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• v.7 no.1
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• pp.107-114
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• 1990

Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-l,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-1,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.

• Journal of the Korean Chemical Society
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• v.62 no.4
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• pp.265-268
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• 2018

The solvolyses of anthraquinone-2-carbonyl chloride (1) were studied kinetically in 27 pure and various mixed solvents. The analysis using the extended Grunwald-Winstein equation in the solvolyses of anthraquinone-2-carbonyl chloride (1) obtained the l value of $2.11{\pm}0.11$, the m value of $0.54{\pm}0.06$, and the correlation coefficient of 0.955. The solvolysis reaction of 1 might proceed via an associative $S_N2$ mechanism enhancing bond making than bond breaking in the transition state (TS). This interpretation is further supported by a relatively large solvent kinetic isotope effect (SKIE, 2.27).

• Journal of the Korean Chemical Society
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• v.65 no.5
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• pp.309-312
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• 2021

The solvolysis of (1s)-(+)-menthyl chloroformate (1) were studied kinetically in 28 pure and various mixed solvents. The analysis using the extended Grunwald-Winstein equation in the solvolysis of 1 obtained the l value of 2.46 ± 0.18, the m value of 0.91 ± 0.07, and the correlation coefficient of 0.950. The solvolysis of 1 might proceed via an associative S_N2 mechanism enhancing bond making than bond breaking in the transition state (TS). The value of l/m is 2.7 within the ranges of value found in associative S_N2 reaction. This interpretation is further supported by a relatively large solvent kinetic isotope effect (SKIE, 2.16).

• The Korean Journal of Food And Nutrition
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• v.28 no.5
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• pp.866-870
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• 2015

In this study, coffee waste was extracted with different solvents such as ethyl acetate, methylene chloride and methanol to investigate the total polyphenol contents, electron donating ability and the inhibitory effect on glutathione S-transferase. The total polyphenol contents were $3,060.61{\pm}357.12{\mu}g\;GAE/mL$ in ethyl acetate, $909.09{\pm}35.71{\mu}g\;GAE/mL$ in methylene chloride, and $1,602.27{\pm}30.36{\mu}g\;GAE/mL$ in methanol. The total polyphenol contents showed a significant difference (p<0.05) between the solvents. The electron donating ability was $80.20{\pm}1.45%$ for ethyl acetate, $81.94{\pm}0.45%$ for methylene chloride, and $85.14{\pm}1.53%$ for methanol. The electron donating abilities were significantly different (p<0.05) between the solvents. The inhibitory effect of the various extracts on glutathione S-transferase (% inhibition) was $92.12{\pm}0.56%$, $88.48{\pm}0245%$ with methylene chloride extract, and $90.85{\pm}0.14%$ with methanol extract. These too were significant different (p<0.05) between the solvents. The two portions of coffee waste extracts obtained from ethyl acetate and methanol showed meaningful results on the total polyphenol contents, and the inhibition effects on glutathione S-transferase. Therefore, they can be utilized to develop health care foods and can be applied as antioxidants for cosmeceuticals.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.46-51
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• 2008

The objective of this study was to investigate antioxidant activities of freeze-dried, main root, and fine root of ginseng (Panax ginseng CA. Meyer), which were extracted with various solvents including ethanol, methanol, and water. Ethanol extracts in both parts showed the most powerful scavenging activities against DPPH radicals. Especially, ethanol extract of fine root had higher reducing power and antioxidant capacity than that of main root. The highest antioxidant activity in linoleic acid emulsion system was also observed in fine root extracted with ethanol, followed by methanol and water. Both ferrous ion chelating activity and ferric reducing antioxidant power (FRAP) of extracts were increased with the increase of extracts concentration. These results suggest that ethanol extract of fine root of ginseng has the most effective antioxidant capacity compared to the methanol and water extracts tested in the present study. Thus it can be applied for the effective extraction of functional material from ginseng for the usage of pharmaceutical and/or food industries.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1050-1059
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• 2019

The self diffusion, hole volume, and flow thermodynamic parameters of polyamide fibers were calculated from rheological parameters and crystallite size in order to study of flow segments in amorphous region. The stress relaxation of polyamide filament fibers were carried out in air and various solvents at various temperatures using the tensile tester with the solvent chamber. The rheological parameters were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Ree-Eyring and Maxwell non-Newtonian model. It was observed that the rheological parameters of these polyamide filament fibers are directly related to the relaxation spectra, self diffusion, viscosities, and activation energies of flow segments.

• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.435-439
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• 2008

Due to the fact that tocopherols and tocotrienols have antioxidant and anticancer properties, the commercial utilization of unsaponifiable fractions in rice bran is increasing. These nutraceutical compounds, however, are fairly unstable and readily break down when exposed to oxygen or lighting conditions. To compare the relative sensitivity of vit E isomers to heat and oxygen, concentrated unsaponifiable fractions extracted from crude rice bran oil were exposed to various temperature, oxygen (nitrogen-balanced), and bathing solvent conditions and resultant concentration changes in ${\alpha}$- and ${\gamma}$-tocopherols (T) and tocotrienols (T3) were evaluated. Each isomer exhibited different heat stability. Among them, ${\alpha}$-T3 degraded more rapidly compared to other vit E isomers while ${\alpha}$-T was the most stable isomer. Oxygen level also showed significant impact on each isomer's stability where severe reductions of ${\gamma}$-T (by 20%) and ${\gamma}$-T3 (by 29%) were observed under 2% oxygen conditions, while under 0% oxygen conditions no degradation could be observed even after exposure to $95^{\circ}C$ for 4 hours. When various blending solvents were mixed with concentrated unsaponifiable fractions, organic solvents such as isooctane and hexane were more effective in maintaining the stability of ${\gamma}$- T3 compared to edible oils, among which com oil was more efficient than soybean and rice bran oils.